Ecco the Dolphin (エコー・ザ・ドルフィン) is an action-adventure game developed by Ed Annunziata and Novotrade International and published by Sega for the Mega Drive/Genesis in 1992.

The player character is a bottlenose dolphin who travels through time to combat hostile extraterrestrials in Earth's oceans and on an alien spacecraft.

Two features of the gameplay are based on actual dolphin habits: one button causes Ecco to sing, allowing him to speak with other cetaceans and interact with certain objects.

Upon leaving the bay, Ecco swims around meeting other marine life including other dolphins who tell them they have felt the storm and the entire ocean is in chaos.

Arriving in the Arctic after a long journey through the ocean, Ecco finds the Big Blue, who says that the storms occur every 500 years.

Though the Big Blue doesn't know what causes the storms, he suggests that Ecco should seek the Asterite, the oldest life form on Earth.

To his dismay, though the Asterite would otherwise have the power to aid Ecco, it currently can't, as some orbs from its body were lost a long time ago.

The Asterite tells Ecco to go to the sunken ruins of the city of Atlantis, where he can use the time machine left behind by the Atlanteans to retrieve the orbs.

From the library, Ecco learns about the source of the storms: an alien race known as the Vortex lost the ability to produce food on their planet.

After receiving the globe, the Asterite grants him the power to turn his sonar into a deadly weapon against the Vortex, as well as the abilities to breathe underwater and to slowly regenerate lost health.

When the Queen is defeated, she spits out Ecco's pod, and the dolphins make their collective escape back to Earth.

[8] After deciding to create a game based around dolphins, developer Ed Annunziata carried out research on the subject and was particularly inspired by the book Sounding by Hank Searls which explained how the creatures use echolocation.

[9] Annunziata worked with the music team on the soundtrack, playing them songs by Pink Floyd to illustrate the feeling he was aiming for.

Panicked, Annunziata turned to his boss Clyde Grossman who suggested Echo, which alluded to the dolphin's echolocation ability.

Being of Italian descent, he chose the spelling Ecco, because it can loosely mean "I see" in that language, and "seeing with sound" is what echolocation enables dolphins to do.

[11][12][13] Another explanation is that it references John C. Lilly, a controversial scientist who believed in an alien organization called the Earth Coincidence Control Office or E.C.C.O.

An enhanced Sega CD version that features new and redesigned levels and an alternate Red Book audio soundtrack, composed by Spencer Nilsen, was also released.

In 2002, Sega's first attempt to enter the downloadable retail game content business occurred on the digital storefront RealOne Arcade.

Along with stereoscopic 3D graphics and the option to choose between Japanese and international versions of the game, the port also adds 'Super Dolphin Mode', which decreases the difficulty by giving players invincibility and unlimited oxygen.